European Patent Application Publication Number 0 475 213 A1 published 18.03.92 Bulletin 92/12 (hereinafter "EP Application") based on U.S. patent applications Ser. Nos. 578,697; 578,696 and 686,956 filed Sep. 4, 1990; Sep. 4, 1990, and Apr. 18, 1991, respectively discloses a thermal insulating glazing unit having an edge assembly having low thermal conductivity and a method of making same. In general, the EP Application teaches a thermal insulating glazing unit having a pair of glass sheets about and sealed to an edge assembly to provide a sealed compartment between the sheets. The edge assembly includes a spacer frame having a generally U shaped cross section having a sealant on each of the outer surfaces of the upright legs, and optionally on the outer surface of the base of the spacer frame and an adhesive bead having desiccant therein adhered to inner surface of the base of the spacer frame.
U.S. Pat. No. 5,177,916 issuing on U.S. patent application Ser. No. 578,697 filed Sep. 4, 1990, discloses a flat metal substrate that may be formed into spacer stock and thereafter formed into a spacer frame for use in the manufacture of an insulating unit of the type disclosed in the EP Application. The spacer stock disclosed in U.S. Pat. No. 5,177,916 has a pair of outer legs spaced from one another and joined to one another by a base.
European Patent Application No. 90 304 456.8 discloses an insulating unit having a pair of glass sheets separated by and secured to a spacer frame having a "W" shape cross section.
Although the design of the spacer stock and/or spacer frame disclosed in the EP Application, U.S. Pat. No. 5,177,916 and European Patent Application No. 90 304 456.8 is acceptable, it has limitations. More particularly, the spacer stock has incremental torsional twist because the legs of the spacer stock and/or spacer frame are only interconnected by the base. As can be appreciated, as the length of the spacer stock or sides of the spacer frame between adjacent corners increases the degree of twist of the spacer stock between the ends or the sides of the spacer frame between adjacent corners increases.
As can be appreciated by those skilled in the art of making multi-sheet glazing units, it would be advantageous to provide a spacer stock design that minimizes if not eliminates torsional twist of the spacer stock and/or of the subsequently formed spacer frame for ease of handling the spacer stock/spacer frame during fabrication of a multi-sheet glazing unit.